The overarching goal of the project is to develop, test, and explore a novel platform based on a new class of ultracold molecules with unprecedentedly large polar interactions, one to two orders of magnitude larger than for existing ultracold molecular species. This platform will enable a unique series of experiments to study controlled collisions and novel phenomena at the transition from few- and many-body physics.

Molecules with electric dipole moments experience anisotropic long-range interactions and at ultracold temperatures, the quantum nature of these interactions enables applications in quantum chemistry, quantum simulation and quantum computation. The selection of molecules was so far limited to molecules that can be directly laser-cooled or that are composed from ultracold alkali atoms. By contrast, UltraMeDiQs will use optical tweezer arrays as a versatile approach to associate individual ultracold silver (Ag) and cesium (Cs) atoms to molecules. CsAg features an almost ionic bond and therefore a remarkably large electric dipole moment — large enough to create for the first time ultracold molecular ensembles deep in the strongly interacting regime.

The high dipole moment of CsAg makes it also an ideal candidate to investigate so-called field-linked molecules with lifetimes exceeding 10 s. This in turn will enable the deterministic study of (in)elastic collisions involving these states, the formation of weakly bound metal cluster states, and the potential expansion of these clusters to many-body states. UltraMeDiQs will investigate few- and many-body mesoscopic quantum systems with large dipolar interactions using CsAg as constituents in optical tweezer arrays and optical lattices. The flexibility of the platform and tunability of the dipole interaction will, for instance, enable the simulation of topological optical phonons in a wide range of lattice configurations and the formation of dipolar quantum Wigner crystals.